; entry.asm: Entrypoint for the loader partition of the Nightloader.

; WARNING: Never import at the top of this file!
; If something has to be included, include it at the bottom!

STACK_SIZE          equ 32768
UPPER_STACK_POINTER equ 0x100000
LOWER_STACK_POINTER equ (UPPER_STACK_POINTER - STACK_SIZE)

bits 16
org 0xa000
entry:
    mov ebx, LOWER_STACK_POINTER
    mov ss, ebx
    mov esp, STACK_SIZE
    mov ebp, STACK_SIZE
    push dx

.check_a20:
    push ebp
    mov ebp, esp
    call check_a20_wraparound
    mov esp, ebp
    pop ebp
    cmp eax, 1
    je .a20_is_enabled

    cli
    hlt

.a20_is_enabled:
    ; jmp .flat_gdt_loaded

    ; Reset Display
    mov ah, 0x00
    mov al, 0x03
    int 0x10

    ; mov ah, 0x05
    ; mov al, 0
    ; int 0x10

    mov ah, 0x0b
    mov bh, 0x00
    mov bl, 0
    int 0x10

    push ebp
    mov ebp, esp
    call setup_drivers
    mov esp, ebp
    pop ebp

    mov edi, ebp
    mov esi, esp
    push ebp
    mov ebp, esp
    push .flat_gdt_loaded
    call load_flat_gdt
    mov esp, ebp
    pop ebp
.flat_gdt_loaded:
    mov ebp, edi
    mov esp, esi

    mov ebx, some_text
    push ebp
    mov ebp, esp
    push dword ebx
    call dword write_text
    mov esp, ebp
    pop ebp

    cli
    hlt
some_text:
    db "This is some text.", 0x00

; Utilities
%include "utility/math.asm"
%include "utility/memory.asm"

; Memory Management
%include "memory/a20.asm"
%include "memory/gdt.asm"

; Driver Manager
; %include "drivers/manager.asm"